Electrical contact device



Oct. 17, 1961 A. MOTTU ETAL ELECTRICAL CONTACT DEVICE Filed Sept. 8, 1959 I II III I!!! Vldwzrll/W [III III United States Patent Ofice Patented Oct. 17, 1961 3,005,078 ELECTRICAL CONTACT DEVICE Andre Mottu and Germain Rollat, Geneva, Switzerland,

assignors to Societe Genevoise dlnstruments de Physique, Geneva, Switzerland, a firm of Switzerland Filed Sept. 8, 1959, Ser. No. 838,708

Claims priority, application Switzerland Sept. 18, 1958 2 Claims. (Cl. 200-166) This invention has as its object an electrical contact device, one of the contacts of which comprises a conductive piston and a spring applying the latter against the other contact.

This device is characterised by a protective insulating sleeve which surrounds the piston, is displaceable along the axis of the latter and is also subjected to the action of a second spring, which urges it against the other contact.

The drawing shows, by way of example, two embodiments of the device according to the present invention. In the drawings:

FIGURE 1 is an axial section through a first embodiment.

FIGURE 2 is an axial section through a second embodiment.

The contact device shown in FIGURE 1 is intended for an electro-magnetic clutch, housed in a casing A. It comprises two contacts, one consisting of a conductive rotary ring 1 and the other of a brush comprising a conductive piston 2, which is mounted in a sheath 3 screwed into the casing A and bears on the said ring. A conductive terminal 4 terminates in the conductor 5 and supports an insulating sleeve 6, The terminal and the sleeve are clamped against a shoulder 3a on the sheath 3 by the nut 7. A second insulating sleeve 8, is mounted to slide axially in .the sheath 3 under the action of a spiral spring 9 which urges it towards the outside, it being guided in this movement by a screw 10, engaged in a rectilinear groove 11 in the sleeve. The conductive piston 2 can slide in the sleeve 8 which surrounds it and is urged outwardly by a spiral spring 12, housed in the two sleeves 6 and 8. A conductor soldered to two studs, one 4a provided on the terminal 4 and the other 2a on the piston 2.

In the position of use, the piston 2 and the sleeve 8 are urged against the ring 1, the first by the spring 12 and the second by the spring 9; in this way, the sleeve 8 serves as a protection for the piston 2 and, in particular, prevents it from coming into contact with dust or particles of oil.

The embodiment shown in FIGURE 2 differs from the first by the feature that the insulating sleeve 6 is replaced by an insulating sleeve 14, which extends over the whole height of the sheath 3 and slightly beyond it. The piston 2 slides completely inside this sleeve, and outside the sheath 3 slides the protecting sleeve 15 which is urged outwardly by the spiral spring 16, bearing on the sheath, the screw 17 engaged in the groove 18 in the sleeve serving as an axial guide.

What we claim is:

1. An electrical contact device for maintaining contact with a movable conductor surface comprising in combination, a sheath means for attaching to a support adjacent said movable conductor surface, a piston contact means slidably mounted in said sheath means for making electrical contact with said movable conductor surface, a biasing means for urging said piston to contact said movable conductorsurface, a non-conducting guide bearing means slidably mounted intermediate and concentric with said sheath and said piston for insulating and guiding said piston in its movements, and a second biasing means for urging said non-conducting guide bearing means to contact said movable conductor surface thereby providing complete insulation and guide bearing for said piston contact means between said sheath and said movable contact surface.

2. An electricalcontact device for maintaining electrical contact between stationary and movable conductor surfaces, said device comprising in combination; a metal tubular sheath means having oppositely disposed ends, flanged at one said end and having means intermediate said ends for attaching said device to a supporting structure with the unflanged end extending toward, and separated a spaced distance from, said movable conductor surface; non-conducting guide-bearing means slidably mounted in said sheath means for extending across said spaced distance and slidably contacting the movable conductor surface; biasing means intermediate the guidebearing means and the sheath means for biasing the guide-bearing means toward said movable conductor surface; conductive piston means slidably mounted in said non-conducting guide-bearing means for extending across said spaced distance and slidably contacting said movable conductor surface; second biasing means mounted in said sheath means for biasing said piston means toward said movable conductor surface; a fixed non-conducting sleeve mounted in said sheath means in alignment with the guide-bearing means and intermediate said second bias ing means and said sheath means for insulating said second biasing means from said sheath means, electrical terminal means fixed in said flanged end of said sheath means and extending externally thereof for electrically connecting with said stationary conductor surface; and a flexible electrical conductor means for electrically conmeeting said terminal means with said piston means; whereby said piston means extending from said sheath means across said spaced distance to said movable conductor surface is supported and guided in guide-bearing means extending therebetwcen and insulated from all electrical connection with any elements other than said movable conductor surface.

References Cited in the file of this patent UNITED STATES PATENTS 1,158,083 Stout Oct. 26, 1915 2,269,614 Von Soden Jan. 13, 1942 2,889,530 Straub et a1. June 2, 1959 

